br Table Characteristics of all patients in the registry and
Table 1 Characteristics of all patients in the registry, and those identified to have regional nodal recurrences as a site of first failure
Abbreviations: BCS Z Breast Conserving Therapy; ECE Z extracapsular extension; ER Z Solasodine receptor; LN Z lymph node; LVI Z lymphovascular invasion.
586 DeSelm et al. International Journal of Radiation Oncology Biology Physics
Fig. 1. Condensed axial views of nodal recurrences (NR), with suggested contours that maximally encompass the re-currences in each axial plane while minimally targeting surrounding tissues not involved in regional tumor spread. After radiation therapy, NRs are in red and NRs in patients without previous RT are in yellow. A full view of recurrences and recommended contours is shown in Fig. E1. r> posterior regions of the SCV. We defined the medial SCV as posterior to the SCM muscle, lateral SCV as the fat space lateral to the SCM muscle, and posterior SCV as the fat space posterior to the patient’s transverse process (mid-spinal canal; Fig. E1; available online at https://doi.org/10. 1016/j.ijrobp.2018.10.021). The RTOG SCV definition correlates to our medial SCV. Nearly half (48%; 28/58) of SCV NRs occurred in the medial SCV, followed by 40% (22/58) in the lateral SCV and 14% (8/58) in the posterior SCV. All 8 of the patients with posterior SCV NR had grade 3 disease; 38% of them (3/8) had LVI and only 12.5% of them (1/8) had ECE. The average size of the primary tumor size was 1.8 cm, and 60% of tumors (6/10) were node negative at the time of initial treatment. Despite not clearly having high-risk disease at baseline by current clinico-pathologic factors, nearly all (7/8) patients with posterior
SCV NR not only developed synchronous recurrences in the axilla, but 75% (6/8) also developed synchronous distant metastases.
We next examined the pattern of SCV failure among patients who received RT to the SCV versus those who did not, hypothesizing that if a region of the SCV were repeatedly undercovered using conventional techniques, the undercovered region might exhibit more failures over time. We identified 1103 patients who underwent RT to the regional nodes, which included the SCV in all of these patients, in addition to the IMNs in 202 (18%). Patients who received RNI were significantly higher risk at baseline, with a 7.7-cm versus 2.2-cm average primary tumor, a median of 4 versus 0 positive nodes, significantly more LVI, ECE, higher grade, and lower ER positivity (Table 2). Despite these findings, the rate of relapse in the medial
Nodal recurrences in breast cancer 587
Table 2 Characteristics of patients identified to have had RNI and those who had no RNI
Receipt of chemotherapy 98%* 63%
Abbreviations: BCS Z breast conserving therapy; ECE Z extracapsular extension; ER Z estrogen receptor; HER2 Z human epidermal growth factor receptor 2; LN Z lymph node; LVI Z lymphovascular invasion; RNI Z regional nodal irradiation; RT Z radiation therapy.
SCV was not significantly different among the high-risk patients who received RNI. However, the rate of relapse in the lateral SCV was significantly higher in the patients who received RNI (P Z .009; Fig. 2).
Only 2/58 SCV NRs occurred above the cricoid carti-lage. Both NRs were at the level of the hyoid bone and posterior to the SCM in patients who were treated previ-ously with adjuvant RT and were not encompassed within the RTOG or ESTRO CTV groups.
superior border of the clavicle and first rib, whereas none occurred above the superior border of the clavicle or below the third intercostal space. There were 2 IMN NRs abutting the sternum >5 mm medial to the internal mammary ves-sels (outside the ESTRO guidelines), suggesting that the majority of IMNs were included within CTV coverage that extended all the way to the sternal border.